What if it's President Harris, but a GOP Senate? That's her allies' fear.

Should Kamala Harris win in November, her administration could begin in the weakest starting position of any in a generation. Her allies are already fretting over what to do about it.

Democrats close to the vice president have grown increasingly worried that Republicans will flip the Senate next month even if Harris wins — a scenario that would make Harris the first president since George H.W. Bush to start her term without a majority in the upper chamber.

The fears have sparked a flurry of post-election scenario planning across the Democratic Party, according to interviews with more than a half-dozen advisers and allies, even as Harris remains locked in a tight race with less than three weeks left to go.

Harris allies have sought creative ways to install a Cabinet should a Republican Senate refuse to confirm her picks, including extending current Biden officials’ tenure, appointing a slate of acting secretaries or — in one long-shot scenario making the rounds in Democratic circles — even jamming through some nominees before Harris officially takes office.

Others are gaming out the legislative battles over tax policy and government funding that will define 2025, debating which of her top policy priorities can be folded into must-pass packages — and what trade-offs will be necessary to secure them.

A GOP-controlled Senate would pose an immediate threat to Harris’ presidential ambitions, narrowing her personnel choices, sharply limiting her policy agenda and curbing her influence on any Supreme Court vacancies. Lacking much in the way of personal cross-aisle relationships with Senate Republicans, Harris, they worry, would have to spend her crucial first days mired in a search for compromise.

"No matter what, I think it's going to be a very difficult time for the next two years if the scenario is Harris wins the presidency but loses the Senate," said former Republican Sen. Chuck Hagel, who has endorsed Harris. "I suspect that she will have some Republicans who will work with her. I don't think that will be the majority or anywhere near it in the Republican caucus."

Harris’ transition preparations are already well behind schedule, given the vice president’s late entry into the race. Past presidential transitions have begun work as much as six months before Election Day; Harris only became the nominee in the last three months.

But the historically rare scenario Harris would likely face makes that planning all the more crucial, those involved said, to ensure she enters the Oval Office with a clear strategy that can overcome hard-line Republican opposition — and minimize the Democratic infighting over policy and personnel that could squander her narrow window of opportunity.

They described an early presidency that would be necessarily more moderate and compromise-oriented in its leadership and legislative ambitions under a split-government scenario, yet clear-eyed about the areas where Harris believes she can still build on the Biden administration’s progress: health care, taxes and housing.

“There’s a lot of balancing act here,” one outside adviser said of narrowing Harris’ expansive campaign platform down to a more pragmatic agenda. “But that means she has to pick and choose amongst her children. And children don’t like to be left out.”

Harris spokespeople declined to weigh in on transition planning, with campaign aides instead pointing to the work they’ve done to head off a potential Republican Senate. The campaign has so far transferred nearly $25 million to the Democratic Senatorial Campaign Committee and other groups focused on electing down-ballot Democrats.

“Vice President Harris is working hard to help Democrats win key Senate and House races so we can have a coalition ready on day one to take action to lower costs for the American people, protect reproductive freedom, and other key priorities,” said Mia Ehrenberg, a campaign spokesperson.

Not since Bush’s election in 1988 has a president taken office without allies controlling the Senate. The last time a Democrat won the White House alongside a GOP Senate was more than a century before that, when Grover Cleveland was first elected in 1884.

This time around, few believe Harris would be afforded much leeway in stocking her government or advancing her priorities from Republican senators incentivized to fight her agenda at every turn.

Hagel, a Nebraska Republican who served as Defense secretary during the Obama administration, expressed faith that former President Donald Trump's hold on the GOP would break if he loses again. But he doubted it would make Harris' presidency much easier.

"There will be, certainly, a right-wing group of Republicans — I don't know how many — who will essentially block everything that she tries to do," said Hagel, who now works on veterans issues as chair of the Veterans Justice Commission at the Council on Criminal Justice.

Democrats both inside and outside the Harris camp have explored a range of ideas for staffing her administration in the face of GOP resistance, such as keeping some senior Biden officials in their current roles. While Cabinet officials customarily offer their resignation at the end of an administration, their Senate confirmations do not expire, providing a potential lifeline to a Harris administration. Harris could also temporarily promote certain aides into Cabinet jobs without Senate confirmation, where they could then serve as acting secretaries for months before facing a vote.

Some are floating a bolder strategy: Ask President Joe Biden to nominate some of Harris’ picks during the post-election lame-duck period, allowing Democrats to rush them through Senate confirmation before losing control of the chamber on Jan. 3, 2025.

But Harris advisers have so far downplayed the viability of that option, citing logistical hurdles and concerns the preemptive gambit would torch what little bipartisan goodwill might otherwise exist.

Harris is instead likely to take a more deliberate approach to staffing up, relying on scores of Biden aides willing to stay on to run her administration while her nominees wind their way through the confirmation process. In 2021, Biden had the vast majority of his Cabinet in place by March. While Harris will certainly want to bring in her own people, doing so could take notably longer than that.

“There’s not going to be the rush necessarily to get your team in place because this is partly her team,” said former Sen. Doug Jones (D-Ala.), who nevertheless expressed confidence Democrats could still keep the Senate. “She can get her administration up and running seamlessly without having to put forth a single name.”

Those new nominees will in some cases be more moderate so as to win a couple Republican votes, advisers and allies conceded. Former lawmakers and longtime congressional staffers also become more appealing for Cabinet jobs, given their ties to Capitol Hill. And inevitably, at least one nominee won’t make it through — more than two-thirds of the tie-breaking votes Harris has taken as vice president have been related to confirming political appointees.

Despite the angst over personnel, most Democrats involved in the transition discussions argued Harris needs to preserve her political capital for the string of legislative fights in her first months — including a major tax policy bill, government funding deadlines and a potential debt ceiling clash that could once again put the economy at risk.

Those must-pass bills have diminished typical split-government concerns that nothing will get done. Instead, Democrats believe they’ll need to winnow her priorities in an effort to manage expectations within the party and head off jockeying among interest groups.

That likely means dropping some of the loftier aims that have energized Democratic voters, like codifying Roe v. Wade, which would first require 51 votes to eliminate the filibuster. And there remain grave, unanswered concerns about Harris' ability to fill a hypothetical Supreme Court vacancy should Republicans refuse to grant her nominee a hearing.

"Once you start going up the chain with judges it gets tougher and tougher," said Jones. "I think the timing is going to be interesting if there is a Supreme Court pick."

Harris allies have focused on expanding the Child Tax Credit and extending generous Obamacare subsidies as achievable top goals in a first term, as well as other child care investments that Republicans may agree to in exchange for preserving some of the Trump-era tax cuts due to expire next year.

Several of those allies also emphasized the need to push for a separate bipartisan package on par with the infrastructure law that Biden signed in his first year, pointing to housing as a potential area where Harris could seek 60 votes for a bill stuffed with incentives for developers to build more and expanded aid for renters and homebuyers.

“If the margins are close, then the administration has a lot of juice for those things,” said another Democrat working on the policy planning, adding that there’s hope some Republicans will also be inclined to support broadly popular ideas like expanding limits on insulin prices.

Still, Harris allies acknowledged achieving any of those goals will take concerted outreach and relationship building, especially with the few Republican moderates who would suddenly wield outsize power, like Sens. Susan Collins of Maine and Lisa Murkowski of Alaska. They view the work Harris did on the Senate Intelligence Committee — which earned the praise of several Republican members — and the dinners she hosted with GOP women in the Senate as a model.

And some hope that her outreach to Republicans during the campaign — including rallying with former Rep. Liz Cheney (R-Wyo.) and promising to appoint a Republican to her Cabinet — will prove helpful when it comes to governing.

But there are limits. Neither Murkowski nor Collins has publicly expressed support or even faint praise for Harris’ candidacy. And perhaps more important will be Harris’ relationship with whomever would be the Senate majority leader, who controls what legislation or nominees even get a chance at a floor vote.

Harris has no apparent relationship with the one of the frontrunners for the job, Sen. John Thune of South Dakota. Harris did sit on two of the same Senate committees as the other lead candidate, Sen. John Cornyn of Texas, occasionally working together. But that overlap has done little to soften Cornyn's harsh attacks in recent months on Harris' work on immigration issues.

Still, Harris’ allies are holding out hope for a post-Trump fracturing of the GOP that might push some faction of Republican senators closer to the center — or at very least, convince them it’s worth it for their own political futures to open a channel to a Harris administration.

“The task ahead is to win, and then see what happens,” said Jim Kessler, executive vice president for policy at the centrist Democratic think tank Third Way. “You’ve got all these members that spent $60 million and fought like hell to get there, and they’re going to say eventually, ‘I want to do something. I want to get something done.’”